Baffled by a UPS

[analog_sa]

My new UPS seems really incapable of supplying light loads. It would supply a 200W load for over 30 minutes but lightly loaded or not loaded at all it switches off in exactly 5 min. This seems like some type of a safety feature but for the life of me i can't see the purpose. Is this common? My other, very old UPS, certainly does not behave the same way. Any ideas if it is possible to modify this?

 

[Elvee]

Hi,

There might be a logic to it:
if it senses no load for a period of time, it decides it is not in use, and shuts down in order to save the batteries.
I would imagine this kind of "feature" can be disabled via the console or dip switches (unless it is endorsed by Microsoft, off course).
LV

 

[analog_sa]

Quite likely. A very annoying "feature" which makes it impossible to power up items with low consumption like ADSL modems/routers or laptops. I wonder if this is common with other modern UPSs. If it does indeed sense the output current, there is likely to be a sense resistor in series with the output, right? Sadly, no dip switches, pots or any possibility for adjustments.